Streams that receive groundwater discharge are gaining streams. The level of water in the stream is below the water table. This is also true for lakes and wetlands that receive groundwater discharge. More than half of the total flow of some streams during dry periods is from groundwater discharge.
Streams that allow water to seep into groundwater are known as losing streams. This occurs when the water table drops below the stream level.
This section, including most illustrations, was adapted with permission from "What is Groundwater?" by Lyle Raymond, Jr. (© Cornell Cooperative Extension, Cornell University, July 1988).